This invention relates to a process for the preparation of 17.beta.-oxalyl steroids. It is known that numerous 17.beta. -oxalyl steroids of the general Formula I are pharmacologically effective compounds (Belgian Pat. No. 779,869). The process of this invention makes it possible to produce these compounds in a three-stage synthesis with a simple mode of operation from 17-oxo steroids, because the starting 20-cyano steroids of the process can be conventionally synthesized in a two-step synthesis from the corresponding 17-oxo steroids (J. Chem. Soc., [London],1952, 161; J. Org. Chem. 30, 165, 2715; and U.S. Pat. No. 3,079,385).